Cancer holds the most fatal disease in the statistics of mortality, so that anti-cancer agents have been a matter of continued concern. Conventional anti-cancer agents have much toxicity to affect normal cells since they are lack of specificity to cancer cells, which results in a variety adverse effects such as depilation, lowering of immunity and liver function, etc.
Considering the above, various researches have been carried out to obtain natural anti-cancer agents from all sorts of food having no or little adverse effect. As a result, it is revealed that β-D-glucan obtained from mushroom mycelia and isoflavone contained in soybean, etc. have anti-cancer effect.
β-D-glucan is a main bioactive component in mushroom. It is found that the anti-cancer activity of mushroom derives from the activation of immunocyte by β-D-glucan to delay the progress of cancer and to prevent the transition of cancer. Accordingly, β-D-glucan may be used along with cancer treatment to improve the effect.
β-D-glucan, extract from mycelium culture of mushroom, is produced on a commercial scale in some advanced countries. For example, AHCC, which is imported from Japan, is produced by mixing extracts from mycelium cultures of seven mushrooms and is distributed through sales network for hospital to cancer patients. Further, arabinoxylan, which is extract from Lentinus edodes mycelia, is distributed in the US. In Korea, extract of Phellinus linteus mycelia, which is produced on a commercial scale by the trade name of Mesima-EX (HAN KOOK SIN YAK Corp, Korea), is on the clinical test.
The extracts of mushroom mycelium culture commercialized by this time have not been distributed on a large scale since the extraction process costs very high. The amount of extract of mushroom mycelium culture, that is, the amount of polysaccharides depends on the cultivation period of mushroom and the growth rate of mycelia. In general, the cultivation period of Lentinus edodes, Phellinus linteus, Ganoderma lucidum, etc. is long and the growth of mycelia is slow, which limits the amount of extracts.
The polysaccharides extracted from mycelium culture require to be hydrolyzed to medium or low molecular weight polysaccharides in order to be absorbed easily in the body. However, the enzyme for the hydrolyzation is hard to obtain, which makes the cost high. Further, the method of separating and purifying the medium or low molecular weight polysaccharides produced from the hydrolyzation has technical difficulty, so that the yield is very low.
Isoflavone, contained mainly in soybean, exists as aglycon form (e.g., daidzein, genistein or glycitein), as glycoside form thereof (e.g., daidzin, genistin or glycitin), as acetylglycoside thereof (e.g., acetylglucose), or as malonylglycoside thereof (e.g., malonylglucose). It is found that isoflavone has anti-mutagenic and anti-cancer effect. The anti-cancer effect of isoflavone is mainly caused by genistein in the aglycon form, and the glycoside form is not known to have anti-cancer effect.
Considering the above, efforts have continued for the development of an anti-cancer agent with immunoenhancing effect, without affecting adversely on normal cell, and a method of preparing the agent in great quantities with low cost.